Garbage incinerator and method of operation

ABSTRACT

A system for disposing of garbage and gaining useful heat output from controlled burning of the garbage is provided and is particularly adapted for decentralized locations in a community. The garbage is dumped into a feed hopper and piled to a substantial depth with the forward face of substantial crosssectional area being acted upon by rotating shredders; the garbage being continuously fed forward by the endless belt support at the bottom of the hopper. A second series of shredders serves to completely shred and masticate the garbage into fine particles and project the same into a combined compressing and pulverizing station. Continuous ignition is provided by a heatretaining wall immediately downstream. Solid particles, glass and metal are removed by transverse conveyors at critical locations along the system. Computer control of the operating components and auxiliary fuel injection maintains full efficiency in the incinerator chamber. Heat exchange means is provided for useful heat output with expansion and scrubber chambers immediately downstream thereof. Steam is injected to move the relaxed gaseous products and to precipitate out minute solid products; the gaseous products being forced to the bottom of the unit to assist the precipitation and to thus minimize air pollution. A melting cupola for glass or other thermoplastic material receives heat from the incinerator chamber with continuous casting of such byproducts and cutting into blocks.

United States Patent Smith 5] Mar. 7, 1972 [54] GARBAGE INCINERATOR AND METHOD OF OPERATION [72] Inventor: Ray F. Smith, 25 South Ogontz, York, Pa.

[22] Filed: Dec. 12, 1969 [21] Appl. No.: 884,471

2,029,725 2/1936 Kuhner ..1 10/8 3,357,380 12/1967 Siracusa... ...l l0/8 3,482,533 12/1969 Ankersen ..110/8 Primary Examiner-Arthur D. Kellogg An0mey-Lowe and King [57] ABSTRACT A system for disposing of garbage and gaining useful heat output from controlled burning of the garbage is provided and is particularly adapted for decentralized locations in a community. The garbage is dumped into a feed hopper and piled to a substantial depth with the forward face of substantial crosssectional area being acted upon by rotating shredders; the garbage being continuously fed forward by the endless belt support at the bottom of the hopper. A second series of shredders serves to completely shred and masticate the garbage into fine particles and project the same into a combined compressing and pulverizing station. Continuous ignition is provided by a heat-retaining wall immediately downstream. Solid particles, glass and metal are removed by transverse conveyors at critical locations along the system. Computer control of the operating components and auxiliary fuel injection maintains full efficiency in the incinerator chamber. Heat exchange means is provided for useful heat output with expansion and scrubber chambers immediately downstream thereof. Steam is injected to move the relaxed gaseous products and to precipitate out minute solid products; the gaseous products being forced to the bottom of the unit to assist the precipitation and to thus minimize air pollution. A melting cupola for glass or other thermoplastic material receives heat from the incinerator chamber with continuous casting of such byproducts and cutting into blocks.

45 Claims, 6 Drawlng Figures PATENTEUMAR 7 I972 SHEET 2 OF 4 INVENTUR,

64% E 5M/7H PATENTEDMAH 7 I972 SHEET 3 OF 4 1 N VEN TOR fl/Wf SM/M ATTORNEYS GARBAGE INCINERATOR AND METHOD OF OPERATION The present invention relates to incinerators for waste material and, more particularly, to an apparatus and method for burning garbage to minimize air pollution and maximize useful heat output.

BACKGROUND OF THE INVENTION With the population of the country and the world increasing at an extremely rapid rate in recent years, the density of population in the cities has increased considerably. Also, high-density population and working areas in the suburbs are now becoming commonplace as the increased traffic on the roads and highways makes it more difficult to transport workers to and from work. As the density of population in a limited area is thus increased, the problem of refuse and garbage disposal becomes more acute. The paperwork explosion of our technological society and the increase in the need for keeping written records on every aspect of private and public life has greatly increased the paper refuse generated by the office to add to the burden of these population centers. With the burden increasing in geometrical proportions and prior methods of disposal proving to be unable to cope with it, public officials have relatively recently turned to the last resort the large scale use of garbage for land fills. However, now this is coming under increased attack by citizens, not only for aesthetic reasons, but also for the health hazard which uncovered garbage presents. Furthermore, when the large amounts of garbage must be transported over long distances to land fills for disposal, the inefficiency in terms of manpower and equipment is staggering.

There is thus a need for an improved system of garbage disposal and specifically a system to successfully decentralize garbage disposal for the high-density population centers thereby allowing disposal on the spot, while at the same time assuring that the system does not subject the atmosphere to pollution. Also, as a desirable added feature of such a disposal system, it should be self-sustaining in operation and even provide additional work output for producing electrical power and heat for the population center.

Furthermore, it is contemplated that heat producing disposal systems may be used to produce marketable byproducts using only raw materials from the garbage or refuse itself, which will greatly assist in amortization of the system. To briefly explain one aspect of this, in recent years the technology of producing glass cheaply has led to the adoption of disposable or one-way glass bottles and containers, especially for the food and soft drink industries. Heretofore, this glass has been disposed of by burying in a land fill along with the rest of the garbage. However, glass in the form of cast ingots can have substantial salvage value for use in several ways depending upon the quality of the recovered glass. lf the quality is high, theglass can be shipped back to the glass manufacturer where it is processed and utilized again to make containers or other consumer products. In most instances, however, because of impurities and difference in quality of the glass collected, it is not suitable for reuse, but may be used for other purposes in the form of block or ingots such as for low cost building material. Of course, because of the inherent resistance of the glass blocks to moisture and the weather, buildings made of these blocks need no painting or other maintenance. Also, such glass ingots or blocks have use in places where now inefficient material is used, such as water breaks along the seashore and retaining walls for cuts in the earth for highways, canals or the like.

Thus, it is a primary object of the present invention to pro vide a garbage disposal unit and method having a very high efficiency of operation to minimize air pollution and for producing useful heat output.

It is another object of the present invention to provide a garbage apparatus and method which is particularly adapted for use in high-density population centers.

It is another object of the present invention to provide a disposal system for waste material that is made substantially independent of outside support by making efficient use of the of the energy generated from the burning of the refuse and waste to produce electricity and other byproducts.

It is another object of the present invention to provide a system which through shredding, compressing and pulverizing the garbage causes complete combustion to substantially eliminate air pollution.

Another object is to provide such a system that provides efficient burning over a large cross-sectional area.

It is still another object of the present invention to expand the gaseous combustion products in stages and to use steam injection to move the gaseous products and to cause any minute solid particles to precipitate leaving the exhaust free of pollution.

BRIEF DESCRIPTION OF THE INVENTION In broad terms, the system of the present invention allows efficient operation on a large body of garbage to prepare the same for an efficient burning operation. To do this, a series of stacked shredder cylinders forms the forward wall of the hopper and continuously attacks the forward face of a large body or mound of garbage to provide a large cross-sectional area of shredded garbage particles. A second, parallel series of shredder cylinders further shreds and masticates the particles and projects the same into a second stage of operation, which includes a plurality of stacked compressor and pulverizer units. In accordance with the present invention, these units include restricted passageways with plural stage fans for simultaneously pulverizing the particles and compressing the mixture of air and particles to form a more combustible composition. Between the first and second stage fans, fuel injectors are provided for supplying makeup fuel as required, to maintain the desired combustion level in the incinerator chamber.

Just downstream of the compressor and pulverizer units is a heat retaining wall having a plurality of heat sink ports aligned with the compressing and pulverizing passageways. The heat retaining wall provides sutiicient heat to cause spontaneous combustion of the mixture as it is projected into the ports in compressed form. After the burning particles pass through the heat sink ports, entry is made into an open incinerator chamber where constant turbulence caused by the fan and eddy currents insure a complete mixing and burning of the material.

A plurality of endless conveyors extending in a transverse direction along the bottom of the garbage disposal unit receive noncombustible material, such as glass and metal due to the inability of the same to remain airborne through the several stages described. In addition, a transversely extending magnetic conveyor is provided above the feed hopper so that metal parts projected upwardly by the rotation of the shredder cylinders will be attracted thereto and may be removed in a continuous fashion.

In direct communication with the incinerator chamber is a heat exchanger and a first regulating wall is provided immediately downstream thereof to regulate the flow of gaseous combustion products from this area. The restricted size and number of passages in this wall allows the maintenance of high pressure in the incinerator chamber for assuring complete combustion.

An expansion chamber is provided just downstream by positioning of a second regulating wall with an increased crosssectional area over said first wall for release of the gaseous combustion products. This allows slowing of said products to insure complete stripping of the same of useful heat, which is accomplished by cooling fluid passages within the walls. After the gaseous products are thus relaxed, entry is made into a scrubber chamber where steam jets are utilized to maintain movement and to aid precipitation of minute solid combustion products. The scrubber chamber is horseshoeshaped with the legs extending downwardly so that the gaseous products are now caused to go to the bottom of the disposal unit. In doing so, the legs enclose the feed hopper so as to preheat the stacked garbage and insure still further maximum utilization. Extending from the bottom of the unit is the final outlet duct which releases the cleansed gaseous products through assistance of a vacuum fan.

In accordance with an additional feature of the present invention, the garbage disposal unit is provided with a melting cupola for reclaiming waste thermoplastic material. The cupola has a long, inclined neck so that the material is placed in a thin layer for intimate contact with heat-retaining surfaces during melting. The thermoplastic material being recovered may be glass, which has been taken from the garbage supplied to the unit for burning. However, other material such as waste aluminum or other metal and plastic or the like may be reclaimed in alternate shifts of operation of the unit. From the reservoir bowl of the cupola, the thermoplastic material is continuously cast and cut as desired into ingot form.

Still other objects and advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description, wherein I have shown and described only the preferred embodiment of the invention, simply by way of illustration of the best mode contemplated by me of carrying out my invention. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modification in various obvious respects, all without departing from the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.

THE DRAWINGS In the drawings:

FIG. 1 is an overall cross-sectional view of a garbage disposal unit constructed so as to use the principles of the present invention;

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1 showing the inner and outer walled arrangement of construction;

FIG. 3 is a sectional view taken in the direction of line 3-3 showing the intermeshed relationship of the shredding cylinders;

FIG. 4 is a sectional view taken in the direction of line 44 showing the regulating wall construction;

FlG. 5 is a cross-sectional view taken along line 5-5 of FIG. 1 showing the inner and outer wall construction at the front end of the disposal unit; and

FIG. 6 is a schematic diagram showing the operating stages and components in block form for the apparatus and method of the present invention.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. 1 of the drawings wherein a more In the preferred embodiment illustrated, the truck T is adapted to dump its large load of approximately 40 cubic yards of garbage into a large volume hopper, generally designated by the reference numeral 15. As shown in perspective in FIG. 1, a large body of garbage G is thus formed by the successive dumping of trucks and/or trailers with the body G being large enough to accommodate at any one time 20 or so loads of 40 cubic yards each. As such, the body G will. be at least of a height and width of approximately 30 by 30 feet so as to present a cross-sectional front face of at least approximately 900 square feet. It is to be specifically understood that the above capacities and dimensions are shown and described for illustrative purposes to describe a workable arrangement as intended by the present inventive concept; but other sizes of the garbage disposal unit 10 with either greater or lesser capacity and tailored to fit the specific needs of the community being served are within said inventive concept.

The bottom of the hopper 15 is provided by an endless conveyor floor 16; upper run 17 of the same providing a platform to support the body of garbage G. A plurality of forwardly curved spikes 18 are mounted across the full width of the conveyor 16 in order to impale the lower face of the body G and assist in positively urging the same forwardly for the shredding operation, which will now be described.

A shredding station S is formed, in part, by a first series of stacked shredding cylinders, generally designated by the reference numeral 19, which cylinders 19 thus form the front wall of the fed hopper 15. Each cylinder of the series 19 comprises a roll 20 mounted in a horizontal position and having radially projecting teeth 21; said rolls 20 being driven in a clockwise direction (as viewed in FIG. 1) by suitable means (not shown in this figure). The adjacent teeth 21 of the adjacent rolls 20 are intermeshed and the rolls synchronized so that interference will not occur during operation (see FIG. 3). Also as shown in FIG. 3, the teeth are curved forwardly with a sharp knife edge 22 being formed on the leading face thereof in order to efficiently shred and masticate the material being worked on. The spikes 18 on the conveyor 16 are inter digitated with the teeth 21 of the lower cylinder in the series 19 so that interference will not occur at this point. With this interrneshing and interdigitation of the spikes 18 with the teeth 21 and between the teeth 21 themselves, it will readily be seen that a self-cleaning action occurs. Because of the sharp knife edge 22 and the curved configuration of the teeth 21, the efficiency of the shredding action on the garbage is substantially improved so that the front face of the body of garbage G is transposed into a literal wall of particles which are ejected outwardly from the series of cylinders 19 and to the right as viewed in FIG. 1.

The now airborne particles are next caught by a second series of shredder cylinders 23 which further serve to shred and impact the garbage particles. The second series of cylinders 23 also further mix the particles, add additional speed to the procomplete understanding of the features of the P1eselnt invenjection and loosen the particles to assure access to the inner tion can be gained, there is shown a garbage disposal unit 10 in the form of a building, housing the necessary components for garbage disposing by burning and providing useful heat output as intended. An entrance 11 to the garbage disposal unit 10 is provided along the forward wall; a ramp 12 being provided upon which a truck, generally designated by the reference indicia T, may enter the building and dump a large load of garbage. It is to be understood that the ramp 12 is to be raised and insulated from the framework of the building by means of a space 13 which prevents deleterious action of the heat on the truck T, especially the tires. If needed, cooling fluid may be passed through the space 13 for positive cooling of the ramp 12. It is, of course, within the purview of the present invention to provide other transport means other than the truck T, for delivery of the garbage and waste material, such as by feed conveyors. The latter arrangement would be especially adapted for use where the garbage disposal unit 10 is strategically located close to the source of refuse collection, such as in extremely high density population areas composed of high rise apartments and office buildings.

core for eventual exposure to heat for burning. As viewed in FIG. 1, the wall of particles is now being homogeneously projected forwardly along a large cross-sectional area, as schematically represented by upper and lower flow arrows 24, 25.

With the combustible particles such as paper, food leaves, now in very small particles and in an airborne condition, the heavier noncombustible material, such as metal, glass and stones, are desirably allowed to fall by gravity due to their greater weight onto an endless conveyor 26 which extends transversely across the unit 10 below the cylinders 23. It has been found that the greater percentage of this undesirable material will fall out at this initial point so that principally only lightweight, combustible material is projected to the next stage which will be described shortly; however, a secondary conveyor 26a as a backup is provided downstream of the next stage.

In order to further insure separation of metal which may be included in the body of garbage G, an endless conveyor 27 is provided along the upper portion of the hopper 15. This conveyor 27 is magnetized so as to attract any metal material which may be on the top of the body G. It will be understood that once the metal is attached to the conveyor 27 the continuous movement transverse to the unit carried the captured material out of said unit 10 for depositing in a central location.

in order to prevent the upper cylinder of the series 19 from moving large, unshredded chunks of garbage or refuse into the upper area defined by the arrow 24, a static barrier 28 is provided having projecting teeth 29, which are interdigitated with the teeth 21 on the shredder cylinders.

The shredder cylinders 19 are stacked in alignment at an acute angle 0 to the vertical; i.e., the series of cylinders 19 is at a forward relief angle 0 with respect to a line extending perpendicular to the upper run 17 of the conveyor floor 16. This is done for two important reasons. First, the relief angle allows a component of the weight of of the garbage to act against the cylinders 19 to gain a more efficient operating interface with the 21. Secondly, the upper portions of the garbage are allowed to be loosened to permit a more thorough churning action of the garbage caused by the cylinders 19. With this loosening effect, any metal which is held captive in the body of the garbage G is capable of being urged upwardly by the successive clockwise rotation of the cylinders 19 until finally such metals is projected into engagement with the conveyor 27 by the uppermost cylinder of the series 19. The forward face of the body of garbage G is, as will be remembered, constantly fed forward by the conveyor 16. As material is removed, the relief angle 0 allows more material to immediately take its place by caving in of the material due to its own weight. In all respects, an angle 6 of approximately 10 has been found to operate most efficiently; although it is to be understood that other angles may be substituted as desired and dictated by the particular installation.

Thus, to briefly restate again, afier the garbage has thus been shredded in succession by the two series of cylinders 19, 23, the particles of combustible material arrive in air suspension in a continuous flowing wall between the limits of flow arrows 24, 25. At this point, the particles are treated in accordance with an important step of the present invention wherein the particles are pulverized and the mixture of air and particles is simultaneously compressed to insure more efficient combustion. To do this, compressing and pulverizing station CP is provided comprising a plurality of restricted passageways 30 which like the series of cylinders 19, 23 are stacked in the vertical direction. Several vertical rows of the passageways 30 may be provided in order to receive the mixture of air and particles along the full face or wall of the material being advantageously presented for simultaneous combustion. Each of the passageways 30 include first and second stage fans 31, 32 which serve to draw the mixture of air and particles into the passageways 30. The first stage fan 31 serves to compress the mixture, and at the same time, the whirling fan blades serve to impact the particles as they pass through for a further pulverizing and readying of the particles for combustion.

The second stage fan 32 has fan blades with a greater pitch than the blades of the fan 31 so that the mixture is further compressed, as well as pulverized, so that still more efficient combustion is assured.

The intake air drawn by the fans 31, 32 enters through the opening 11, proceeds down through the feed hopper 15, permeates the body of garbage G and passes through the shredder cylinders 19, 23 where the air thus picks up the particles between the limit arrows 24, 25. Fuel injector nozzles 33 are provided between the fans 31, 32 so that supplemental fuel may be added to the system as required, and as will be explained later in detail.

Immediately downstream of the compressing and pulverizing station CP is a heat retaining wall 35 which serves as an ignition station, generally represented by the reference indicia l. in the wall 35 are provided a plurality of heat sink ports 36 which correspond to and are aligned generally with the passageways 30. The heat sink ports 36 are lined with metal,

as are the passageways 30, to improve the wear characteristics thereby preventing deterioration of the walls due to impacting by the particles being sent therethrough.

To the downstream side of the wall 35 is incinerator chamber C where the final and complete combustion of the particles takes place. As the combustion is continuous, the heat from the chamber C serves to heat the wall 35 to at least 200 F. and retain the heat due to its brick and metal construction. As the particles thus leave the final stage fan 32 at the compressing and pulverizing station C1, the heat radiating from each of the ports 36 causes spontaneous combustion and thus initiation of the burning of the garbage particles. The particles are pushed on through the ducts 36 and due to the turbulence caused by the fan 32, the relative small size of the shredded and pulverized particles, and the addition of fuel through the injectors 33, if needed, instantaneous and complete combustion has been found to be induced in the incinerator chamber C.

The solid particles of combustion are precipitated toward the bottom of the unit and come to rest on the transverse conveyors 37 where they may be deposited at an outside location. Because the combustion is clean and relatively free of foreign products which have been taken out at conveyors 26, 26a, the ashes may be collected from the conveyors 37 for use as a highly effective fertilizer or humus fertilizer or humus for plants.

The gaseous combustion products turn upwardly as indicated by the flow arrows 40 and enter a heat exchanger chamber, generally designated by the reference numeral C,. This chamber may comprise any known arrangement of receiving heat, such as steam tubes 41 shown in FIG. 1.

From the heat exchanger chamber C, the gaseous combustion products are pushed through restricted transfer ducts 42 formed in a controlled release barrier 43. By controlled release is meant that the total cross-sectional area of the transfer ducts 42 is less than the total cross-sectional area of the ports 36 so that a super atmospheric pressure is maintained upstream in the combined volume of the incinerator chamber C and the heat exchanger chamber C,.

Just to the downstream side of the barrier 43 is an expansion chamber C defined by a parallel barrier 44 with restricted transfer ducts 45 formed therein. The ducts 45 of the downstream barrier 44 have an overall increased cross-sectional area so as to allow greater flow out of the expansion chamber C; but a cross-sectional area insufficient to allow the gaseous combustion products to expand directly to atmospheric pressure. This feature gives the marked advantage of slowing the combustion products as they pass through the ducts 42, 45 so that cooling fluid 46 within the barriers 43, 44 may be efficiently preheated prior to entering the steam tube 41.

Just downstream of the barrier 44 is a third chamber, which for identification purposes may be referred to as a scrubber chamber C The final expansion occurs here and results in a gaseous body which is becoming lethargic due to its now almost total loss of heat through the various upstream stages described. To thus maintain proper forward movement of the gas through the system, a plurality of nozzles 47 are provided at an acute angle (approximately 450) to the gas flow (see FIG. 1) to mechanically move the combustion products along in the desired path. The stream or water vapor, serves another purpose of forming water droplets around any solid combustion products which have escaped gravitational flow to the conveyors 37. The droplets, of course, are caused by the condensation of the water onto the solid products which serve as an attracting core for the same.

A third and solid barrier wall 50 is provided downstream of the steam nozzles 47 in order to turn the moving gaseous combustion products toward the bottom of the garbage unit 10. As this is done, the gaseous product divides along the apex 5 l of the hopper and flows down the legs of a substantially U shaped duct 53, as best shown in FIG. 5. AS the gaseous combustion product moves down the legs as shown by the dashed line arrows of FIG. 5, the last traces of heat are radiated inwardly to the hopper (see FIG. 1) whereby the body of garbage G is advantageously preheated.

At the bottom of the unit the gaseous combustion product turns the corner and heads upwardly along the outside horseshoe shaped outlet duct 54, and thence through an exhaust stack 55 at the top of the unit 10. Since complete combustion has been induced in the incinerator chamber C by a wide dispersal of the articles being burned, the particles have been slowed for collection by causing expansion in a series of steps through chambers C Cg, C, and since any minute solid particles have been fairly scrubbed in the chamber C: by water vapor supplied through the steam jets 47, the air finally passing to the exhaust stack 55 is extremely clean and no air pollution results. In order to assist exhausting the gaseous products from the unit 10, an exhaust fan 56 driven by a suitable motor 57 may be provided.

From the foregoing, it can be seen that the apparatus and method described does provide an efficient system for disposing of garbage without air pollution, while at the same time gaining maximum useful work output. Schematically, the whole system may be viewed in FIG. 6, wherein the function representing blocks are identified by the station and apparatus identifying indicia of FIG. 1. Thus, to briefly review the operation of the garbage disposal unit 10, the bulk waste input is provided in the form of a body of garbage G which is, in turn, preheated by radiation from both sides as counterflow of the combustion products occurs along the interior U-shaped duct 53 formed by the barrier wall 50. Impacting and shredding occur at station S by operation of the shredding cylinders 19, 23 driven by suitable driving motors 60 (shown only in schematic form in FIG. 6). The conveyor 16 is driven by a suitable motor 60a so as to move the body of garbage G forwardly as required. The shredded particles are next projected to the compressing and pulverizing station CP where the fans 31, 32 perform this function when driven by fan motors 61 (shown only in schematic form in FIG. 6). In addition, at the compressing and pulverizing station CP, any necessary fuel from the injectors 33 is advantageously provided.

Ignition is provided as the particles approach the heat retaining wall 35 with the flame front advantageously being positioned approximately 10 inches downstream of the final stage fan 32 and just upstream of the wall 35. After passing through the heat sink ports 36, the material is brought into the incineration chamber C where complete combustion is assured. The useful heat passes through the heat exchanger chamber C and after losing the substantial portion of its heat, the gaseous products are passed through expansion chamber C and thence on to the scrubber chamber C From the scrubber chamber C the solid combustion products precipitate out and the now cooled and relaxed gaseous products pass downwardly and then upwardly through the outlet duct 54. A suitable final filter 62, if desired, may be provided to assure absolute cleanliness. The exhaust fan 56 is provided only if found to necessary or desirable to maintain the proper exhaust flow rate.

The restraining walls 43, 414 are, as shown in FIG. 6, a preheated for water being introduced into the steam tube 41 of the steam generator of the heat exchange chamber C Makeup water may be provided upstream as indicated by arrow 63 with a suitable condenser 64 also supplying the necessary water. One form of the useful output of the heat exchanger chamber C preferably takes the form of an electric generator 65 which makes the garbage disposal unit 10 selfsufficient by providing the necessary electrical power for the driving motors 60, 60a, and the fan motor 61 and other necessary support equipment. After the superheated steam has been utilized in the electric generator 65, low enthalpy steam can be supplied to the steam injection nozzles 47 through a suitable conduit 64a immediately upstream of the condenser 64.

A plurality of sensors 70 are positioned at a suitable location adjacent the ignition station I for observing a selected parameter of combustion. As presently contemplated, the sensors 70 are to take the form of light-responsive elements which are controllably actuated by changes in color of the flame front which, as will be remembered, is suitably positioned at a location between the compressing and pulverizing station CP and the ignition station I (see FIG. 1). The sensors 70 are interconnected with a suitable combustion control module 71 (FIG. 6) which may be an analog computer so as to be proportionally responsive to the color the flame front being produced. As an example of an operative form of the present invention, if the flame front is colored from blue to yellow in the visual spectrum, the garbage being supplied is providing the proper burning in the incinerator chamber C so that the sensors 70 indicate electrically to the control module or computer 71 that no change in the operating components is required. If the flame front, as sensed by the sensor 70, goes to a dark yellow and red color, then a burning condition in the incinerator chamber C is indicated, which is below normal and correction is required. To do this, the combustion control module 71 may send by lead 72 electrical signals to the fan motors 61 for the fans 31, 32 so that the compressing and pulverizing operation may be immediately stepped up to provide the additional fuel required to take the color back to necessary blue to yellow reading. Feedback from the combustion control module 71 is, in addition, appropriately fed to the driving motors 61) for the shredding operation at the shredding station S through lead 73 and finally to drive motor 60a for the conveyor 16 through lead 74. Thus, each of the motors is stepped up in operation as determined by the module or computer 71. It is to be understood that other sensors, responsive to other parameters or conditions at any of the stations S, CP'or I, and elsewhere, may be utilized to feed information to the module 71 in order to make the controlling operation more sophisticated.

The module or computer 71 also determines if the increase in fuel supplied by the particles of garbage is insufl'rcient whereupon a control signal is fed to the fuel injectors 33 for injecting fuel or increasing the level of injection to compensate for the deficiency in the primary fuel. Of course, as the flame front moves to a bright blue the computer senses this condition through the combustion control module 71 and sends a signal to appropriately reduce the speed of the motors 61, 60,601: and to lower the level of the fuel injection through the fuel injectors 33. With this arrangement, it can be seen that complete selfsustaining control of the garbage disposal unit 10 is gained without need for a human operator.

An additional means for utilizing the useful heat output of the garbage disposal unit 10 of the present invention takes the form of a melting cupola 80, as best shown in FIGS. 1 and 2. The cupola is supportedby spaced walls 81, 82 which are provided with gaseous transfer ports 83, 84 respectively. Through these ports the heated gaseous products of combustion are allowed to proceed around the bottom of the cupola 80 and upwardly over the top, as indicated by the flow arrows in these figures. As such, the base or bowl 85 of the cupola 80 is maintained at a high temperature for maintaining a thermoplastic liquid L in a flowable condition. As the gaseous products extend around the top of the cupola 80 they are returned downwardly through the heat exchange chamber C and proceed through the transfer ducts 42 with the remainder of the gaseous combustion products.

The inner and outer skins 86, 87, respectively, of the cupola 80 are preferably formed of metal to strengthen the same and improve the heat transfer characteristics. The inner skin 86 allows the thermoplastic material being melted to be sealed within the cupola 80 and thereby prevent a possibility of contamination of the heating section. The upper portion of the eupola 80 is formed as a long neck 88 which has a gradual incline from a hopper entrance 89 down to the entry into the bowl 85. With this arrangement the material being melted is allowed to come into intimate contact with the highly heated interior 86 of the cupola 80 in a thin layer contact so that complete melting into a flowable condition is assured (see illustration of this feature in FIG. 1

The hopper entrance 89 may be provided with the end of an endless conveyor 90, which serves to bring the refuse glass to the cupola for melting and reclaiming. It is to be understood that this glass is advantageously collected with the usual garbage collection and brought to the unit in the same truck T, as the remainder of the garbage and is separated either in a separate operation, or as a result of being collected on the conveyors 26, 26a.

The bottles and broken glass as they become heated slide down a long neck 88 and are turned into a layer of molten glass which finally comes to rest in the liquid pool L in the bowl 85. A continuous casting spout 9! (see FIG. 6, also) may be provided at the bottom of the bowl 85 to release a continuous flow of molten glass 92 which in turn may be supported on the suitable conveyor 93 and then cut in a suitable manner into ingots 94 (see FIG. 6, also). A valve 95 having an operator 96 may be used to accurately control the glass-melting operation.

A plug 97 is provided above the level of the liquid L for removal of slag and for inspection purposes. An exterior plug 98 is needed to maintain the heated gas within the exterior wall of the unit and may be removed as necessary to gain access to the plug 97.

It is, of course, possible that the cupola 80 can be used to melt and reclaim other thermoplastic material having salvage value, such as aluminum and other metals which are included in garbage. As such, the necessary separation of the different materials is made and stored at a central location whereupon the working time of the cupola 80 is divided as necessary to reclaim the separate material, all of which materials can be cast in the continuous process illustrated.

In view of the foregoing detailed description, it can now be seen that the broad objects of the present invention have been gained. The shredding of the garbage has been carried out in an efiicient operation wherein the particles are reduced to a size which is readily combustible over a large cross-sectional area, as exemplified by the arrows 24, 25 of FIG. 1. The particles are next simultaneously pulverized and mixture of air and particles compressed by the staged fans 31, 32 to further increase the efficiency of the burning operation. Ignition takes place along a novel ignition wall 35 with complete combustion then being assured in incineration chamber C.

After being extracted of useful heat the gaseous products are allowed to expand in stages through expansion chamber C and scrubber chamber C whereupon maximum retention of heat for preheating purposes is obtained. The now relaxed gaseous products are moved by steam injection from nozzles 47 and any minute solid particles of combustion are precipitated out by fonnation of droplets around the particles; the exhaust after being so cleansed being directed upwardly through outlet duct 54 for release to the atmosphere. Finally, the use of the heat to make the garbage disposal unit selfsustaining and to provide a commercial product in the form of cast ingots of glass and waste metal is made a reality by incorporation of the melting cupola $0.

In this disclosure, there is shown and described only the preferred embodiment of the invention, but, as aforementioned, it is to be understood that the invention is capable of various changes or modifications within the scope of the inventive concept as expressed by the accompanying claims.

[Claim 1. A garbage disposal unit for controlled burning and useful heat output comprising a feed hopper for receiving raw garbage of substantial height, shredding means forming a side of said hopper for transforming said garbage into combustible particles, means for suspending said particles in air to form a mixture in the fonn of a wall of airborne particles substantially corresponding to said side, means for compressing and propelling said mixture of air and said particles and simultaneously pulverizing said particles, means for igniting said mixture, an incinerator chamber for complete combustion of said mixture, and heat exchange means in communication with said chamber for utilizing the heat from said combustion.

2. The combination of claim 1 wherein said igniting means includes a heat retaining wall adjacent said compressing means, said wall having heat sink ports for passage of said mixture, said wall having sufficient heat retention to support spontaneous combustion once placed in operation.

3. The combination of claim 1 wherein is further provided means for injecting auxiliary fuel adjacent said compressing and pulverizing means, and control means for said injecting means to supply said auxiliary fuel as needed to support combustion in said chamber.

4. The combination of claim 1 wherein said compressing and pulverizing means comprises a restricted passage, fan means in said passage, and driving means for said fan means.

5. The combination of claim 4 wherein is further provided control means for regulating the speed of said fan means, said control means being responsive to the state of combustion in said incinerator chamber.

6. The combination of claim 4 wherein said fan means comprises a first stage fan adjacent the entrance of said passage, and an additional stage fan adjacent the exit of said passage, said additional stage fan having a greater pitch to additionally compress said mixture.

7. The combination of claim 1 wherein is further provided an expansion chamber downstream of said heat exchange means, said expansion chamber being defined by a pair of parallel walls, each of said walls having a plurality of passageways through which the gaseous combustion products may pass, the cross-sectional area of the passageways in the upstream wall being less than the area of the passageways in the downstream walls whereby said gaseous products expand for release in a relaxed condition under control of said expansion chamber.

8. The combination of claim 7 wherein said walls include means for passage of cooling fluid, said cooling fluid serving to relax the gaseous combustion products and provide preheated input for said heat exchange means.

9. The combination of claim 7 wherein is further provided a scrubber chamber downstream of said expansion chamber, means for injecting steam into the upper portion of said chamber to move the relaxed gaseous combustion products and to cause water droplets to form about solid combustion products, said chamber extending toward the bottom of said unit to cause said solid particles weighted by said water droplets to fall by gravity to the bottom for collection, and return passage means for directing the scrubbed gaseous product upward for release to the atmosphere, whereby air pollution is avoided.

10. The combination of claim 9 wherein said scrubber chamber is horseshoe shaped with the legs extending toward the bottom of said unit, the legs of said chamber extending on opposite sides of said feed hopper to preheat the garbage to be burned.

11. In a garbage disposal unit for controlled burning and useful heat output, the combination of a feed hopper for receiving raw garbage stacked to a substantial height, conveyor means in said hopper for advancing said garbage, shredder means forming a side of said hopper and covering substantially the full forward face of said garbage operated on so as to provide and then propel a wall of airborne particles, and means for burning said wall of propelled particles over a large flame front substantially corresponding to said forward face.

12. The combination of claim 11 wherein said shredder means includes a series of vertically stacked rotating rolls and cooperating cutting teeth extending radially outward from said rolls.

13. The combination of claim 12 wherein said series of rolls are horizontally mounted and operatively stacked in the verti cal direction at an acute relief angle to the vertical, whereby a component of weight of the garbage acts against said teeth and the operating forward face extends at an acute angle to allow progressively increased looseness in the upper portion of said garbage.

14. The combination of claim 12 wherein is further provided a second series of rolls downstream of the first mentioned series with radially extending teeth, said rolls being stacked so as to extend at said relief angle and serving to cooperate with said first series to further shred said garbage.

15. The combination of claim 14 wherein said teeth of said rolls are intermeshed for self-cleaning action.

16. The combination of claim 15 wherein said conveyor means comprises an endless conveyor forming the floor of said hopper, said conveyor having upwardly extending teeth for impaling said garbage to insure forward movement thereof.

17. The combination of claim 16 wherein said upwardly extending teeth are interrneshed with the adjacent teeth on said rolls for self-cleaning action.

18. The combination of claim 17 wherein said teeth are curved forwardly and include a sharp cutting edge along the concave face thereof for more efficient cutting action.

19. The combination of claim 11 wherein is further provided fan means between said shredder means and said buming means for compressing the mixture of air and particles and for pulverizing said particles.

20. The combination of claim 11 wherein is provided a scrubber chamber downstream of said burning means and having a generally upside-down horseshoe configuration, said scrubber chamber extending downwardly along the sides of said hopper, whereby to cause preheating of said garbage.

21. In a garbage disposal unit for controlled burning and useful heat output, the improvement comprising a feed hopper for receiving multiple truckloads of garbage for burning, endless conveyor means forming the bottom of said hopper, means for driving said endless conveyor means forwardly to advance said garbage, a series of vertically stacked shredder cylinders forming the forward wall of said hopper to simultaneously attack the garbage as the same is advanced by said endless conveyor, whereby a large cross-sectional area of shredded particles of garbage may be supplied for burning.

22. The combination of claim 21 wherein said series of cylinders extends on a line positioned at an acute angle to the vertical, whereby the forward face of said garbage acts by a component of its own weight against said cylinders and said forward face is loosened progressively along the upper portion of said forward face.

23. The combination of claim 22 wherein is provided an additional series of shredder cylinders downstream of the firstmentioned series adapted to cooperate with said first mentioned series for further shredding of said particles.

24, The combination of claim 22 wherein is provided an endless conveyor positioned above the forward wall of said hopper, means for magnetizing the surface of said conveyor to attract metal particles first loosened 25. in a garage disposal unit for controlled burning and specific useful heat output, the improvement comprising a feed hopper for receiving raw garbage, shredding means for transforming said garbage into combustible particles, an incinerator chamber for burning said particles to produce heat, a cupola mounted within said unit and in communication with said incinerator chamber for liquifying thermoplastic material, a hopper for introducing raw material to said cupola, means for withdrawing the said material in liquefied form, and means for casting said material to form solid ingot.

26. The combination of claim 25 wherein said cupola extends longitudinally along said unit over substantially the full length thereof, said cupola having a neck portion extending at a gradual incline and a connected bowl portion, whereby material introduced at said hopper is melted in thin layer contact with said neck and permitted to run along said neck into said bowl.

27. The combination of claim 26 wherein said cupola is lined with metal for efficient transfer of heat to said material.

28. The combination of claim 25 wherein said thermoplastic material is glass.

29. A method of garbage disposing to gain controlled buming in a combustion supporting gas and useful heat output comprising the steps of l. forming said garbage into a bulk mass of substantial height;

2. shredding the garbage to be burned into particles along the substantial height of one side of the mass;

3. maintaining a sufficient gaseous flow to suspend said shredded particles in said gas to form a mixture in the form of a wall of gas borne particles substantially corresponding to said side; and

4. thereafter processing said mixture for burning.

30. The method of claim 43 wherein is further provided the steps of (l) serially relaxing and slowing the gaseous combustion products by allowing the same to expand in plural stages to allow maximum heat transfer and whereby the solid particles of combustion will be slowed for capture.

31. The method of claim 30 wherein is further provided the step of (l) injecting steam after at least partial relaxing and slowing of said gaseous combustion products to maintain movement of the same and to capture said solid particles for disposal by precipitation by forming water droplets therearound.

32. The method of claim 31 wherein (1) said gaseous combustion products are directed in a downward direction after at least partial relaxing and slowing to induce the solid particles to precipitate out.

33. The method of claim 32 wherein (l said gaseous combustion products are reversely directed upwardly in a cleansed condition for release to the atmosphere.

34. The method of claim 29 wherein is provided the additional step of preheating said garbage in said bulk mass to promote formation of more highly combustible particles.

35. The method of claim 43 wherein said step of utilization of said heat includes (1) melting of thermoplastic material, and (2) casting said material into ingots.

36. The method of claim 29 wherein is provided the step of (1) separating noncombustible material from said suspended particles.

37. The method of claim 29 wherein is provided the step of 1 injecting fuel into said mixture and (2) controlling said injection in response to the sensed conditions during the combustion.

38. The method of claim 42 wherein is provided the step of (l controlling the compressing of said mixture in response to the sensed conditions during the combustion.

39. A method of garbage disposing to gain controlled burning and useful heat output comprising the steps of l. forming said garbage into a bulk mass;

2. shredding the garbage to be burned into particles;

3. suspending said particles in air to form a mixture;

4. igniting said mixture;

5. inducing complete combustion of said particles;

6. sensing the temperature of the flame front of said combustion; and

7. controlling the rate of shredding of said garbage and the flow of the mixture in response to said temperature of flame front to maintain a substantially constant level of combustion.

40. The method of claim 39 wherein is included the additional step of (l) injecting auxiliary fuel into said mixture and (2) controlling the injection responsive to the sensing of said temperature.

41. The method of claim 39 wherein is included the additional step of (l) compressing and pulverizing said mixture and (2) controlling the compression and pulverization responsive to the sensing of said temperature.

42. The method of claim 29 wherein said processing step includes the steps of 1. compressing said suspended mixture;

2. simultaneously with said compressing step, pulverizing said particles; and

3. igniting said mixture.

43. The method of claim 42 wherein is further provided the steps of l. inducing complete combustion of said particles; and

2. utilizing the heat from said combustion.

44. The method of claim 29 wherein said gas is air.

sensed by flame front color. 

2. The combination of claim 1 wherein said igniting means includes a heat retaining wall adjacent said compressing means, said wall having heat sink ports for passage of said mixture, said wall having sufficient heat retention to support spontaneous combustion once placed in operation.
 2. shredding the garbage to be burned into particles along the substantial height of one side of the mass;
 2. shredding the garbage to be burned into particles;
 2. simultaneously with said compressing step, pulverizing said particles; and
 2. utilizing the heat from said combustion.
 3. igniting said mixture.
 3. suspending said particles in air to form a mixture;
 3. maintaining a sufficient gaseous flow to suspend said shredded particles in said gas to form a mixture in the form of a wall of gas borne particles substantially corresponding to said side; and
 3. The combination of claim 1 wherein is further provided means for injecting auxiliary fuel adjacent said compressing and pulverizing means, and control means for said injecting means to supply said auxiliary fuel as needed to support combustion in said chamber.
 4. The combination of claim 1 wherein said compressing and pulverizing means comprises a restricted passage, fan means in said passage, and driving means for said fan means.
 4. thereafter processing said mixture for burning.
 4. igniting said mixture;
 5. inducing complete combustion of said particles;
 5. The combination of claim 4 wherein is further provided control means for regulating the speed of said fan means, said control means being responsive to the state of combustion in said incinerator chamber.
 6. The combination of claim 4 wherein said fan means comprises a first stage fan adjacent the entrance of said passage, and an additional stage fan adjacent the exit of said passage, said additional stage fan having a greater pitch to additionally compress said mixture.
 6. sensing the temperature of the flame front of said combustion; and
 7. controlling the rate of shredding of said garbage and the flow of the mixture in response to said temperature of flame front to maintain a substantially constant level of combustion.
 7. The combination of claim 1 wherein is further provided an expansion chamber downstream of said heat exchange means, said expansion chamber being defined by a pair of parallel walls, each of said walls having a plurality of passageways through which the gaseous combustion products may pass, the cross-sectional area of the passageways in the upstream wall being less than the area of the passageways in the downstream walls whereby said gaseous products expand for release in a relaxed condition under control of said expansion chamber.
 8. The combination of claim 7 wherein said walls include means for passage of cooling fluid, said cooling fluid serving to relax the gaseous combustion products and provide preheated input for said heat exchange means.
 9. The combination of claim 7 wherein is further provided a scrubber chamber downstream of said expansion chamber, means for injecting steam into the upper portion of said chamber to move the relaxed gaseous combustion products and to cause water droplets to form about solid combustion products, said chamber extending toward the bottom of said unit to cause said solid particles weighted by said water droplets to fall by gravity to the bottom for collection, and return passage means for directing the scrubbed gaseous product upward for release to the atmosphere, whereby air pollution is avoided.
 10. The combination of claim 9 wherein said scrubber chamber is horseshoe shaped with the legs extending toward the bottom of said unit, the legs of said chamber extending on opposite sides of said feed hopper to preheat the garbage to be burned.
 11. In a garbage disposal unit for controlled burning and useful heat output, the combination of a feed hopper for receiving raw garbage stacked to a substantial height, conveyor means in said hopper for advancing said garbage, shredder means forming a side of said hopper and covering substantially the full forward face of said garbage operated on so as to provide and then propel a wall of airborne particles, and means for burning said wall of propelled particles over a large flame front substantially corresponding to said forward face.
 12. The combination of claim 11 wherein said shredder means includes a series of vertically stacked rotating rolls and cooperating cutting teeth extending radially outward from said rolls.
 13. The combination of claim 12 wherein said series of rolls are horizontally mounted and operatively stacked in the vertical direction at an acute relief angle to the vertical, whereby a component of weight of the garbage acts against said teeth and the operating forward face extends at an acute angle to allow progressively increased looseness in the upper portion of said garbage.
 14. The combination of claim 12 wherein is further provided a second series of rolls downstream of the first mentioned series with radially extending teeth, said rolls being stacked so as to extend at said relief angle and serving to cooperate with said first series to further shred said garbage.
 15. The combination of claim 14 wherein said teeth of said rolls are intermeshed for self-cleaning action.
 16. The combination of claim 15 wherein said conveyor means comprises an endless conveyor forming the floor of said hopper, said conveyor having upwardly extending teeth for impaling said garbage to insure forward movement thereof.
 17. The combination of claim 16 wherein said upwardly extending teeth are intermeshed with the adjacent teeth on said rolls for self-cleaning action.
 18. The combination of claim 17 wherein said teeth are curved forwardly and include a sharp cutting edge along the concave face thereof for more efficient cutting action.
 19. The combination of claim 11 wherein is further provided fan means between said shredder means and said burning means for compressing the mixture of air and particles and for pulverizing said particles.
 20. The combination of claim 11 wherein is provided a scrubber chamber downstream of said burning means and having a generally upside-down horseshoe configuration, said scrubber chamber extending downwardly along the sides of said hopper, whereby to cause preheating of said garbage.
 21. In a garbage disposal unit for controlled burning and useful heat output, the improvement comprising a feed hopper for receiving multiple truckloads of garbage for burning, endless conveyor means forming the bottom of said hopper, means for driving said endless conveyor means forwardly to advance said garbage, a series of vertically stacked shredder cylinders forming the forward wall of said hopper to simultaneously attack the garbage as the same is advanced by said endless conveyor, whereby a large cross-sectional area of shredded particles of garbage may be supplied for burning.
 22. The combination of claim 21 wherein said series of cylinders extends on a line positioned at an acute angle to the vertical, whereby the forward face of said garbage acts by a component of its own weight against said cylinders and said forward face is loosened progressively along the upper portion of said forward face.
 23. The combination of claim 22 wherein is provided an additional series of shredder cylinders downstream of the first-mentioned series adapted to cooperate with said first mentioned series for further shredding of said particles. 24, The combination of claim 22 wherein is provided an endless conveyor positioned above the forward wall of said hopper, means for magnetizing the surface of said conveyor to attract metal particles first loosened
 25. In a garage disposal unit for controlled burning and specific useful heat output, the improvement comprising a feed hopper for receiving raw garbage, shredding means for transforming said garbage into combustible particles, an incinerator chamber for burning said particles to produce heat, a cupola mounted within said unit and in communication with said incinerator chamber for liquifying thermoplastic material, a hopper for introducing raw material to said cupola, means for withdrawing the said material in liquefied form, and means for casting said material to form solid ingot.
 26. The combination of claim 25 wherein said cupola extends longitudinally along said unit over substantially the full length thereof, said cupola having a neck portion extending at a gradual incline and a connected bowl portion, whereby material introduced at said hopper is melted in thin layer contact with said neck and permitted to run along said neck into said bowl.
 27. The combination of claim 26 wherein said cupola is lined with metal for efficient transfer of heat to said material.
 28. The combination of claim 25 wherein said thermoplastic material is glass.
 29. A method of garbage disposing to gain controlled burning in a combustion supporting gas and useful heat output comprising the stepS of
 30. The method of claim 43 wherein is further provided the steps of (1) serially relaxing and slowing the gaseous combustion products by allowing the same to expand in plural stages to allow maximum heat transfer and whereby the solid particles of combustion will be slowed for capture.
 31. The method of claim 30 wherein is further provided the step of (1) injecting steam after at least partial relaxing and slowing of said gaseous combustion products to maintain movement of the same and to capture said solid particles for disposal by precipitation by forming water droplets therearound.
 32. The method of claim 31 wherein (1) said gaseous combustion products are directed in a downward direction after at least partial relaxing and slowing to induce the solid particles to precipitate out.
 33. The method of claim 32 wherein (1) said gaseous combustion products are reversely directed upwardly in a cleansed condition for release to the atmosphere.
 34. The method of claim 29 wherein is provided the additional step of preheating said garbage in said bulk mass to promote formation of more highly combustible particles.
 35. The method of claim 43 wherein said step of utilization of said heat includes (1) melting of thermoplastic material, and (2) casting said material into ingots.
 36. The method of claim 29 wherein is provided the step of (1) separating noncombustible material from said suspended particles.
 37. The method of claim 29 wherein is provided the step of (1) injecting fuel into said mixture and (2) controlling said injection in response to the sensed conditions during the combustion.
 38. The method of claim 42 wherein is provided the step of (1) controlling the compressing of said mixture in response to the sensed conditions during the combustion.
 39. A method of garbage disposing to gain controlled burning and useful heat output comprising the steps of
 40. The method of claim 39 wherein is included the additional step of (1) injecting auxiliary fuel into said mixture and (2) controlling the injection responsive to the sensing of said temperature.
 41. The method of claim 39 wherein is included the additional step of (1) compressing and pulverizing said mixture and (2) controlling the compression and pulverization responsive to the sensing of said temperature.
 42. The method of claim 29 wherein said processing step includes the steps of
 43. The method of claim 42 wherein is further provided the steps of
 44. The method of claim 29 wherein said gas is air.
 45. The method of claim 39 wherein the temperature is sensed by flame front color. 